The active component of a lightning arrester can be a varistor or spark gap. The varistors, or current variable resistors are composed of zinc oxide assembled by sintering in the shape of a ceramic block. A varistor block has a nonlinear voltage/current characteristic: beyond a certain voltage threshold, the impedance of the varistor drops to allow the evacuation of the current responsible of the overvoltage. When the voltage returns to its normal level, the impedance of the varistor resumes its value at the standby state.
The spark gaps are in turn constituted of two electrodes facing one another in any medium (ambient air or specific gas). Beyond a certain value of current voltage, an electrical arc is established between the electrodes, which allows to evacuate the overvoltage.
In a lightning arrester, the spark gap or the varistor are frequently disposed in a cartridge also comprising two connectors, electrically connected to the electrical installation to be protected.
When a very high current intensity flows through the electrical circuit, electromagnetic forces are generated and can cause the tearing of the cartridge. It is known from the prior art to mechanically reinforce the connection between the cartridge and the electrical installation in order to overcome the forces leading to the tearing of the cartridge. The risk of tearing is thus reduced but not canceled. In addition, the mechanical reinforcements of the connections between the cartridge and the electrical circuit are expensive and generate a lengthening of the cartridge replacement duration.